Visual acuity measurement apparatus

ABSTRACT

Provided herein are devices, systems, methods, apparatuses, and computer program products for determining a visual acuity of a reader. The device includes a display adapted to present a first line of text to the reader and an input device adapted to receive signals corresponding to the first line of text. The device further includes a processor that is adapted to determine a reading score associated with the first line of text, generate an acuity parameter based on the reading score and the first readability vector, and determine the visual acuity of the reader based on the acuity parameter and a reference acuity parameter.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/117,122 filed Aug. 30, 2018, which claims the benefit under 35 U.S.C.§ 119(e) to U.S. Provisional Patent Application No. 62/552,055, filedAug. 30, 2017, entitled “Visual Acuity Measurement Apparatus,” thedisclosures of which are hereby incorporated by reference in theirentirety.

BACKGROUND OF THE INVENTION

Conventional measurements of visual acuity are performed with a chart orcard displaying a text passage that is presented to a reader.Measurements of visual acuity are made by, for example, timing thereader to determine how long the reader takes to complete readingseveral lines of text.

Such measurements are limited in that the lines of text or text passageson the chart or card are unchanging (that is, static). Consequently,such measurements require an administrator of a visual acuity test toprovide a series of cards in order to characterize a reader's responseto text passages with different characteristics. This limitation isparticularly important when the visual acuity test is being performed inthe context of medical treatment. Presenting a patient with multiplecards introduces delays to the testing process that decrease theeffectiveness of the visual acuity measurement.

BRIEF SUMMARY OF THE INVENTION

To address the deficiencies of conventional measurements of visualacuity, in a first embodiment of the current disclosure, a device fordetermining a visual acuity of a reader is provided. The device includesa display adapted to present a first line of text to the reader and aninput device adapted to receive signals corresponding to the first lineof text. The device further includes a processor that is adapted todetermine a reading score associated with the first line of text,generate an acuity parameter based on the reading score and the firstreadability vector, and determine the visual acuity of the reader basedon the acuity parameter and a reference acuity parameter.

In another embodiment of the current disclosure, a computer programproduct for measuring visual acuity of a reader is provided. Thecomputer program product includes a computer-readable non-transitorystorage medium having computer-executable instructions stored thereon.The computer-executable instructions are executable to display a firstline of text to the reader, the line of text being associated with afirst readability vector. The computer-executable instructions arefurther executable to determine a first reading score associated withthe first line of text and generate a first acuity parameter based onthe first reading score and the first readability vector. Havinggenerated a first acuity parameter, the computer-executable instructionsare executable to generate a second acuity parameter by generating asecond readability vector, which is made based on the first acuityparameter. The computer-executable instructions are further executableto display a second line of text, the second line of text associatedwith the second readability vector, and determine a second reading scoreassociated with the second line of text. The second acuity parameter isgenerated based on the second reading score and the second readabilityvector. Finally, a determination is made of the visual acuity of thereader based on the first acuity parameter and the second acuityparameter.

In another embodiment of the present disclosure, a method for measuringvisual acuity of a reader is provided herein. The method includes a stepof displaying a line of text to the reader, where the line of text hasan associated readability vector. The method further includes a step ofdetermining a reading score associated with the line of text andgenerating an acuity parameter based on the reading score and thereadability vector. The method also includes a step of determining thevisual acuity of the reader based on the acuity parameter and areference acuity parameter.

In yet another embodiment of the present disclosure, a softwareapplication (such as a mobile app) is provided for assessing visualacuity and reading speed. Such software may be employed to measure ordetermine the efficacy (that is, effectiveness) of a treatment designedto improve, e.g., patient health or the visual acuity and/or readingspeed of the patient. Examples of such therapies may include, forexample: delivery of a pharmaceutical treatment such as a drug to thepatient, providing glasses to the patient, and/or providing contactlenses to a patient. Such software may be also employed to measure ordetermine a reading aptitude of the reader, or an employment fitness ofthe reader.

Currently such testing is performed manually by providing a patient witha reading card having static text (that is, the text is unmoving andunchanging). In order to evaluate the effectiveness of the therapy atest administrator records the amount of time required by a patient toread static text printed on the reading card. Typically, this time isrecorded with a stopwatch.

In an exemplary embodiment of this disclosure a device is provided to areader (who may be a patient in an example where the efficacy of atherapy is being evaluated by the device). The device includes a displayon which a scrolling line of text dynamically appears. The scrolling ofthe text across the display occurs at a specified rate that is measuredby the device. As the text scrolls across the display, the readerindicates his or her reading of the dynamic text by, for example,reading the text aloud to generate an audible signal corresponding tothe words being read. The audible signal is received by a microphonethat compares the words that are read to the displayed text, to collectdata indicative of characteristics of the reader's reading such as:reading accuracy, visual acuity, and count of words read per minute,and/or speed of reading. Such data may be transmitted via a networkinterface to a central database for comparison with reference data (forexample, reference acuity parameters). In addition, the scrolling textmay vary dynamically the size of the font used to display the text, orother parameters such as a brightness or contrast used to display thetext. By recording the font size, brightness, or contrast associatedwith the text on the screen and comparing the signal to the dataindicative of the characteristics of the reader's reading, an acuityparameter may be generated, such as a reading index indicative of thenumber of words read per minute as a function of font size. In addition,the device can record an amount of time that the patient has spentreading the dynamic text, to generate a measurement of the acuityparameter as a function of time spent.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofthe exemplary embodiments of the subject disclosure, will be betterunderstood when read in conjunction with the appended drawings. For thepurpose of illustrating the subject disclosure, there are shown in thedrawings exemplary embodiments. It should be understood, however, thatthe invention is not limited to the precise arrangements andinstrumentalities shown.

In the drawings:

FIG. 1 is schematic diagram of a device in accordance with an exemplaryembodiment;

FIG. 2 shows a flow chart corresponding to a method in accordance withan exemplary embodiment;

FIG. 3 shows a device for displaying a line of scrolling text inaccordance with an exemplary embodiment; and

FIG. 4 shows components of an exemplary computer that may be used toimplement the system as described herein in accordance with an exemplaryembodiment.

DETAILED DESCRIPTION OF THE INVENTION

Reference will now be made in detail to the various exemplaryembodiments of the subject disclosure illustrated in the accompanyingdrawings. Wherever possible, the same or like reference numbers will beused throughout the drawings to refer to the same or like features. Itshould be noted that the drawings are in simplified form and are notdrawn to precise scale. Certain terminology is used in the followingdescription for convenience only and is not limiting. Directional termssuch as top, bottom, left, right, above, below and diagonal, are usedwith respect to the accompanying drawings. The term “distal” shall meanaway from the center of a body. The term “proximal” shall mean closertowards the center of a body and/or away from the “distal” end. Thewords “inwardly” and “outwardly” refer to directions toward and awayfrom, respectively, the geometric center of the identified element anddesignated parts thereof. Such directional terms used in conjunctionwith the following description of the drawings should not be construedto limit the scope of the subject disclosure in any matter notexplicitly set forth. Additionally, the term “a,” as used in thespecification, means “at least one.” The terminology includes the wordsabove specifically mentioned, derivatives thereof, and words of similarimport.

“About” as used herein when referring to a measurable value such as anamount, a temporal duration, and the like, is meant to encompassvariations of ±20%, ±10%, ±5%, ±1%, and ±0.1% from the specified value,as such variations are appropriate.

Throughout this disclosure, various aspects of the subject disclosurecan be presented in a range format. It should be understood that thedescription in range format is merely for convenience and brevity andshould not be construed as an inflexible limitation on the scope of theexemplary embodiments. Accordingly, the description of a range should beconsidered to have specifically disclosed all the possible subranges aswell as individual numerical values within that range. For example,description of a range such as from 1 to 6 should be considered to havespecifically disclosed subranges such as from 1 to 3, from 1 to 4, from1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well asindividual numbers within that range, for example, 1, 2, 2.7, 3, 4, 5,5.3, and 6. This applies regardless of the breadth of the range.

Furthermore, the described features, advantages and characteristics ofthe exemplary embodiments of the subject disclosure may be combined inany suitable manner in one or more embodiments. One skilled in therelevant art will recognize, in light of the description herein, thatthe exemplary embodiments can be practiced without one or more of thespecific features or advantages of a particular embodiment. In otherinstances, additional features and advantages may be recognized incertain embodiments that may not be present in all exemplary embodimentsof the subject disclosure.

FIG. 1 illustrates an exemplary system 117 for visual acuitymeasurement, in accordance with some embodiments. The system includes adevice 100 in communication with a server 111 over a network 113. In anexemplary embodiment, the device presents text to a reader and receivesinformation from the reader indicative of his or her reading of thetext, in compliance with indicated reading tasks. The device may be, forexample, a tablet computer, a smartphone, a personal digital assistant,a personal computer (PC) such as a desktop or laptop computer, or aheadset with an integrated display such as a virtual reality headset ofa PC. The computing device includes a display 101 that presents dynamictext passages to the reader. In exemplary embodiments, the display maybe a greyscale display or may be a colored display and may allowvariable contrast and colors between the text and the background. Thedevice further includes an input device 103 that may include a joystick,a keyboard, a mouse, a microphone, a camera, or other similar toolssuitable to receive input from a user. In certain exemplary embodiments,the input device may be used to record information indicative of themotion of the reader's eyes as the reader skims the dynamic textpassage, e.g., the line of text. The input device allows the user toprovide an input indicative of the dynamic text that the user isreading. In certain embodiments, the user may provide input indicativeof the dynamic text that he or she is reading by typing in the displayedtext via a keypad. In certain other embodiments, the user may provideinput indicative of the dynamic text by reciting the text aloud as he orshe reads so that a microphone may detect the audio.

The device 100 further includes a processor 105 for analyzing input fromthe reader and for recording timing of various events associated withthe reader's reading. The processor is connected to the display 101 andadapted to provide signals to the display to control the dynamicpresentation of the text. The processor is further adapted to receiveinput from the input device 103 and to process the input to determinecharacteristics of the reader's reading. The device is further connectedto a database 107 and a network interface 109. The database includesinformation regarding reference information corresponding to textpassages that are displayed (such as reference acuity parameterscorresponding to the displayed text passages). Such referenceinformation may be used by the processor in determining characteristicsof the reader's reading.

The network interface 109 may be used to send information relating tothe reader's reading over the network 113 to a central server 111. Thecentral server may store the information, for example, in a centraldatabase 115. The central server may further process the receivedinformation to determine information relating to a reader's visualacuity or reading ability and store the reader's visual acuitymeasurements in the central database.

The network 113 may include one or more networks of the typecommercially available in the marketplace or otherwise suitable forsupporting communication between the device 100 and central server 111in accord with the teachings herein. The network can be wired orwireless, a cellular network, a Local Area Network (LAN), a Wireless LAN(WLAN), a Metropolitan Area Network (MAN), a Wireless MAN (WMAN), a WideArea Network (WAN), a Wireless WAN (WWAN), a Personal Area Network(PAN), a Wireless PAN (WPAN), or a network operating in accordance withexisting IEEE 802.11, 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac,802.16, 802.16d, 802.16e, 802.16m standards or future versions orderivatives of such standards.

FIG. 2 is a flow chart of an exemplary method of measuring visual acuityof a reader, in accordance with some embodiments. A computing devicedisplays a line of text to the reader, where the line of text has anassociated readability vector that includes certain parameters thatdetermine how the display presents the text to the reader (step 201). Inan embodiment, a readability vector includes parameters such as a fontsize, a font color, a background color, a display speed (e.g., a scrollspeed), a brightness, and a contrast.

A reading score associated with the line of text is generated (step203). Such a reading score may be generated, for example, by receivinginput from the reader corresponding to the line of text that has beenpresented. Having received that input, the processor may generate areading score based on the accuracy of the reading (that is, how wellthe received input corresponds to the line of text), the speed of thereading (that is, the amount of time between presentation of the line oftext and the completion of the input indicating the reader's reading ofthe text).

In some embodiments, example input from the reader corresponding to theline of text that has been presented includes audio or keyboard input.For example, the reader may provide input indicative of the dynamic textthat he or she is reading by typing in the displayed text via a keypad,a virtual keyboard, or a physical keyboard. Alternatively, the readermay recite the text aloud as he or she reads so that a microphone maydetect the audio. Based on the received input, the processor maygenerate the reading score based on the accuracy of the reading. Theprocessor may measure how well the received input corresponds to theline of text. For example, if the input is received via keypad, theprocessor may generate the reading score based on a number of correct orincorrect words compared with the displayed line of text. If the inputis received via audio, the processor may determine a number of corrector incorrect words by converting the received audio into a set ofphonemes and comparing the reader's phonemes to a reference phoneme setcorresponding to the dynamic text. Such comparison may be performed bythe processor on the reader's device as the reader is performing theindicated reading tasks. Alternatively, such comparison may be performedafter the reader completes the indicated reading tasks, either by theprocessor on the reader's device or by providing the reader's phonemesto a central server that performs the comparison and transmits theresult to the reader's device.

In further embodiments, if the input is received via audio, theprocessor may detect stops or interruptions in the reader's recitedtext. For example, the processor may identify a stop or interruptionwhen the processor has not received or identified audio after apre-configured time period, such as several seconds. Such stops orinterruptions may indicate that the reader is having trouble withaccuracy or speed of the dynamic text presented for the indicatedreading tasks. Consequently, the present system may adjust the readingscore of the reader downward to reflect detected stops or interruptions.

In some embodiments, the processor may determine the reading score basedon the readability vector associated with the dynamic text. For example,the present system may vary a contrast or brightness of the displayedtext, and determine the effect of such brightness or contrast varianceon the accuracy and speed of the reader. In this way, the present systemis able to measure a contrast sensitivity or a brightness sensitivity ofthe reader, and generate the reading score based on the contrastsensitivity or brightness sensitivity.

An acuity parameter is generated based on the reading score and thereadability vector (step 205). The acuity parameter corresponds to thesuccess of the reader in reading the line of text. By comparing thereader's acuity parameter to a reference acuity parameter, a visualacuity of the reader may be determined (step 207). Note that a referenceacuity parameter typically corresponds to a particular readabilityparameter associated with text.

In certain exemplary embodiments, an assessment of the efficacy (thatis, effectiveness) of a treatment such as a pharmaceutical product or anoptical device (e.g., glasses or contact lenses) may be measured byperiodic measurements of a visual acuity for a reader, such as beforethe treatment is provided and after the treatment is provided. Infurther embodiments, the assessment of the efficacy of the treatment canbe based on an amount and/or duration of change in visual acuitymeasurements for the reader, such as changes in the reader's readingscores or acuity parameters.

In other embodiments, an assessment of a reading aptitude of the readermay be provided by measuring visual acuity for the reader. An individualreading aptitude index may be determined based on an individual visualacuity measurement. A method of assessing fitness of the reader as anemployee candidate for a specified employment role may also be providedby measuring visual acuity for the reader. Alternatively, readingaptitude or employment fitness may be assessed over time based onanalysis of periodic measurements of visual acuity.

In still other exemplary embodiments, a method of detecting changes inthe reader's eye (that is, optical or ophthalmic changes) may beprovided using periodic measurements of visual acuity for a reader. As anon-limiting example, the present visual acuity measurements can be usedto detect a presence of changes in a retina of the reader. The macula isa region near the center of the retina that provides finedetail-oriented vision for a patient. Early detection of damage to themacula or retina, such as age-related macular degeneration (AMD), isdesirable to provide a wide range of treatment options for the patient.For example, visual acuity data from periodic visual acuity measurementsmay be used for early detection of a presence of unwanted macula orretina changes. If the present system detects absolute or relativechanges in periodic measurements of the patient's acuity parameters orreading scores, then the present system may trigger an alert,notification, or other indication suggesting that the patient seekophthalmic or other medical treatment. Although AMD is described as onenon-limiting example, the present visual acuity measurements may be usedfor early detection of retinal diseases such as diabetic retinopathy,lattice degeneration, epiretinal membrane or macular pucker, macularhole, central serous retinopathy, retinopathy of prematurity, uveitis,or other diseases of the retina and vitreous.

Detecting change in visual acuity measurements for the reader may beperformed based on analysis of changes in absolute reading scores,absolute acuity parameters, relative reading scores, or relative acuityparameters. The changes may optionally be measured over specifieddurations of periodic visual acuity measurements. The periodic visualacuity measurements may be tracked for an individual reader, or based ondata-driven analytic assessments such as analytics performed on big datasets that are aggregated and sampled from multiple readers. Periodicvisual acuity measurements may be compared over specified periods oftime such as days, weeks, months, or years.

Further embodiments of the present methods may perform statisticalanalysis on a set of visual acuity measurements to detect changes invisual acuity measurements. The present system may track change overtime in a reader's visual acuity measurements, and trigger an alert,notification, or other indication if a decline or improvement in thevisual acuity measurements is identified to be greater than astatistically significant amount. For example, the present system maytrack periodic average, mean, median, minimum, or maximum visual acuitymeasurements over time for a reader, and trigger an alert ornotification if a subsequent visual acuity measurement declines orimproves by an amount larger than a standard deviation or variance froma previous visual acuity measurement (or average, mean, or medianthereof). The present system may also provide detection of potentialoptical or ophthalmic issues in a reader by identifying and comparingreference patterns of declines, such as patterns of declines determinedfrom reference visual acuity measurements. The reference visual acuitymeasurements may be identified from patterns of decline in individualpatients who are identified to be similar to the reader, or fromaggregate patterns of decline in aggregate patient populations.

Some embodiments of the present visual acuity system may associatevisual acuity scores with two- or three-dimensional images of theretina. Such images may be captured using, for example, opticalcoherence tomography (OCT) during a patient visit and timestamped with adate and time of the visit. The present system may identify a relevanttime period associated with changes in a reader's visual acuitymeasurements. The present system may use the identified time period tosuggest associated OCT images of the reader for review, for example, asa detection mechanism to determine whether medical treatment may beindicated as beneficial to the reader.

In some embodiments, the reader's eye movement may be tracked as theline of text scrolls dynamically across the display in order to generatean eye movement factor corresponding to the reader's response to a lineof text with a particular readability vector. Such an eye movementfactor may be incorporated into the measurement of the reader's visualacuity (e.g., the reader's acuity parameter or reading score) and mayalso be stored with the measurement of the reader's visual acuity to beincorporated into a diagnostic assessment of the reader's readingability, visual acuity, and/or overall optical or ophthalmic health. Thepresent system may generate the eye movement factor based on inputreceived from the reader from the input device 103. For example, thepresent system may receive image or video data from the camera on theinput device. The image data may be processed to detect the reader'spupil(s) or movement thereof, and generate an associated eye tracknumber reflecting the detection of the reader's pupil(s) or the motionof the reader's eye(s).

In an embodiment, as described earlier, the system may receive from theuser a first input indicative of dynamic text that the user is reading,such as audio or keyboard input relating to lines or passages of dynamictext. The present system may use the reader's eye movement factor as asecond input indicative of the dynamic text that the reader is reading.For example, the system may use image or video input to detect thereader's pupils and confirm that the reader is looking at the displayeddynamic text and complying with indicated reading tasks. Accordingly,the system can generate the eye movement factor to measure the extent towhich the reader is compliant with the indicated reading tasks from thesystem, based on the detected motion of the reader's eye and the readingspeed of the reader.

Alternatively, the present system may track motion of the reader's eyeto detect voluntary or involuntary eye movement. For example, the systemmay process image or video input from the input device's camera todetect voluntary or involuntary movement of the reader's pupils.Detected voluntary motion can provide a second input indicative of thedynamic text that the reader is reading, for example to confirmcompliance with indicated reading tasks from the system. Detectedinvoluntary motion can provide an input into the reader's visual acuitymeasurements, including the generated eye track number, eye movementfactor, the reading speed, the reading score, or the acuity parameter ofthe reader. For example, the present system can detect involuntarymotion by processing groups of images or sequential image frames fromimage or video input received from the input device's camera, to detectand compare the reader's pupils across image groups or frames. Anystagmus refers to an ophthalmic condition in which a patient's eyesmake repetitive, involuntary movements that can result in reducedvision. These involuntary movements can occur from side to side(horizontal nystagmus), up and down (vertical nystagmus), or in acircular pattern (rotational nystagmus). The present system may generatean eye movement factor to account for a determination that a reader hasa nystagmus, and update the reader's reading score or acuity parameterbased on the generated eye movement factor. Accordingly, the system cangenerate the eye movement factor to measure the reader's compliance withindicated reading tasks or to detect clinically relevant eye motion thatcould affect indicated reading tasks, based on the detected motion ofthe reader's eye and the reading speed of the reader.

In various embodiments, the method steps described herein, including themethod steps described in FIG. 2 may be performed in an order differentfrom the particular order described or shown. In other embodiments,other steps may be provided, or steps may be eliminated, from thedescribed methods.

FIG. 3 shows an example tablet device 300 in accordance with anembodiment. The device includes a display 301, an input menu 303suitable to receive user input via a touch screen, a background 305, anda line of text 307.

Systems, apparatus, and methods described herein may be implementedusing digital circuitry, or using one or more computers using well-knowncomputer processors, memory units, storage devices, computer software,and other components. Typically, a computer includes a processor forexecuting instructions and one or more memories for storing instructionsand data. A computer may also include, or be coupled to, one or moremass storage devices, such as one or more magnetic disks, internal harddisks and removable disks, magneto-optical disks, optical disks, etc.

Systems, apparatus, and methods described herein may be implementedusing computers operating in a client-server relationship. For example,in an exemplary embodiment, processor 105 may act as a client withrespect to a server 111 that may act as a server with respect to othernetworked devices. Typically, in such a system 117, the client computersare located remotely from the server computer and interact via a network113. The client-server relationship may be defined and controlled bycomputer programs running on the respective client and server computers.

Systems, apparatus, and methods described herein may be used within anetwork-based cloud computing system. In such a network-based cloudcomputing system, a server 111 or another processor that is connected toa network 113 communicates with one or more client computers 100 via thenetwork. A client computer may communicate with the server via a networkbrowser application residing and operating on the client computer, forexample. A client computer may store data on the server and access thedata via the network. A client computer may transmit requests for data,or requests for online services, to the server via the network. Theserver may perform requested services and provide data to the clientcomputer(s). The server may also transmit data adapted to cause a clientcomputer to perform a specified function, e.g., to perform acalculation, to display specified data on a screen, etc. For example,the server may transmit a request adapted to cause a client computer toperform one or more of the method steps described herein, including oneor more of the steps of FIG. 2. Alternatively, for example, the clientor clients may transmit a request adapted to cause a server computer orcomputers to perform one or more of the method steps described herein,including one or more of the steps of FIG. 2. Certain steps of themethods described herein, including one or more of the steps of FIG. 2,may be performed by a server or by another processor in a network-basedcloud-computing system. Certain steps of the methods described herein,including one or more of the steps of FIG. 2, may be performed by aclient computer in a network-based cloud computing system. The steps ofthe methods described herein, including one or more of the steps of FIG.2, may be performed by a server and/or by a client computer in anetwork-based cloud computing system, in any combination.

Systems, apparatus, and methods described herein may be implementedusing a computer program product tangibly embodied in an informationcarrier, e.g., in a non-transitory machine-readable storage device, forexecution by a programmable processor; and the method steps describedherein, including one or more of the steps of FIG. 2, may be implementedusing one or more computer programs that are executable by such aprocessor. A computer program is a set of computer program instructionsthat may be used, directly or indirectly, in a computer to perform acertain activity or bring about a certain result. A computer program maybe written in any form of programming language, including compiled orinterpreted languages, and it may be deployed in any form, including asa stand-alone program or as a module, component, subroutine, or otherunit suitable for use in a computing environment.

A high-level block diagram of an exemplary computer that may be used toimplement systems, apparatus and methods described herein is illustratedin FIG. 4. Computer 400 comprises a processor 401 operatively coupled toa data storage device 402 and a memory 403. Processor 401 controls theoverall operation of computer 400 by executing computer programinstructions that define such operations. The computer programinstructions may be stored in data storage device 402, or othercomputer-readable medium, and loaded into memory 403 when execution ofthe computer program instructions is desired. Thus, the method steps ofFIG. 2 may be defined by the computer program instructions stored inmemory 403 and/or data storage device 402 and controlled by theprocessor 401 executing the computer program instructions. For example,the computer program instructions may be implemented as computerexecutable code programmed by one skilled in the art to perform analgorithm defined by the method steps of FIG. 2. Accordingly, byexecuting the computer program instructions, the processor 401 executesan algorithm defined by the method steps of FIG. 2. Computer 400 alsoincludes one or more network interfaces 404 for communicating with otherdevices via a network. Computer 400 also includes one or moreinput/output devices 405 that enable user interaction with computer 400(e.g., display, keyboard, mouse, speakers, microphone, camera, buttons,etc.).

Processor 401 may include both general and special purposemicroprocessors, and may be the sole processor or one of multipleprocessors of computer 400. Processor 401 may comprise one or morecentral processing units

(CPUs), for example. Processor 401, data storage device 402, and/ormemory 403 may include, be supplemented by, or incorporated in, one ormore application-specific integrated circuits (ASICs) and/or one or morefield programmable gate arrays (FPGAs).

Data storage device 402 and memory 403 each comprise a tangiblenon-transitory computer-readable storage medium. Data storage device402, and memory 403, may each include high-speed random access memory,such as dynamic random access memory (DRAM), static random access memory(SRAM), double data rate synchronous dynamic random access memory (DDRRAM), or other random access solid state memory devices, and may includenon-volatile memory, such as one or more magnetic disk storage devicessuch as internal hard disks and removable disks, magneto-optical diskstorage devices, optical disk storage devices, flash memory devices,semiconductor memory devices, such as erasable programmable read-onlymemory (EPROM), electrically erasable programmable read-only memory(EEPROM), compact disc read-only memory (CD-ROM), digital versatile discread-only memory (DVD-ROM) disks, or other non-volatile solid statestorage devices.

Input/output devices 405 may further include peripherals, such as aprinter, scanner, display screen, etc. For example, input/output devices405 may include a display device such as a cathode ray tube (CRT) orliquid crystal display (LCD) monitor for displaying information to theuser, a keyboard, and a pointing device such as a mouse or a trackballby which the user can provide input to computer 400.

Any or all of the systems and apparatus discussed herein, includingparts such as system 117, device 100, server 111, or processor 105 andcomponents thereof, may be implemented using a computer such as computer400.

One skilled in the art will recognize that an implementation of anactual computer or computer system may have other structures and maycontain other components as well, and that FIG. 4 is a high levelrepresentation of some of the components of such a computer forillustrative purposes.

While the subject disclosure has been described with reference toexemplary embodiments, it will be appreciated by those skilled in theart that various changes may be made and equivalents may be substitutedfor elements thereof without departing from the scope of the subjectdisclosure. For example, additional components and steps can be added tothe devices and the various visual acuity measurement methods. Inaddition, modifications may be made to adapt a particular situation ormaterial to the teachings of the exemplary embodiments without departingfrom the essential scope thereof. It is to be understood, therefore,that the exemplary embodiments not be limited to the particular aspectsdisclosed, but it is intended to cover modifications within the spiritand scope of the subject disclosure as defined by the appended claims.

I claim:
 1. A device for determining a visual acuity of a reader, thedevice comprising: a display adapted to present a first line of text; aninput device adapted to receive signals associated with the first lineof text; and a processor configured to: determine a score associatedwith the first line of text; generate a parameter based on the score;and determine a visual acuity based on the parameter.